Portal Chess

Portal Chess is a variant, invented by David Howe in 1997.

Description

Portal Chess is a chess variant that addresses the problem of one player
or the other getting to make the first move. This is solved by splitting
the board up into two boards and letting each player go first on their
board. Players may move pieces from one board to the other only under
very limited conditions.

Note that this variant is a general modifier and may be applied to
many other chess variants in addition to usual or normal chess. Below
I describe its application to normal chess.

Movement rules are as in orthodox chess. Once a piece is touched, it must be moved.
Once you let go of a piece after it has been moved, that move may not be taken back.

Moving pieces between boards (teleporting).
To move a piece from one board to
the other, the piece must be on one of the portal
squares (a square marked with an asterisk (*)).
When it is the player's move on the board where the piece is to be transferred
from...

The player waits for the opponent to make their move, then
states their intention to teleport, but moves no pieces.

On the next turn, the player waits for their opponent to move.

The player then takes
the piece from its current board and places it
on the corresponding square on the other board (eg. from *A1 to *B1).
This counts as the player's
move (ie. the player may not also make a normal move, nor may they declare
intent to teleport).

If an opposing piece occupies the square being teleported to,
it is captured.

If a friendly piece occupies the square being teleported
to, the teleport
is not allowed. If the player cannot teleport after
declaring intent to teleport,
their turn is simply lost.

The teleporting player may cause their King to be exposed by teleporting
a piece that is blocking check.
This is allowed because it will be their turn on that board next.
The player has simply caused themselves to be put in check.

A declaration to teleport does not specify a particular
piece, only the intent to teleport. The piece to be moved is decided when the
player is actually about to move a piece to the other board.

Both players may declare intent to teleport on the same turn. In this case, the moving of the pieces between boards is considered to be simultaneous. If both players
have a choice of which piece to teleport, then they should each write
down the piece they intend to move. After both players have written their move,
they show each other and the moves are made.

Moving a King into check. Here are some instances where a King is being moved into
check (or is already in check). These are considered to be illegal moves:

At the beginning of a turn, player 1 moves their King onto a portal square
and player 2 has a piece on the corresponding portal square on the
other board.

At the beginning of a turn, player 1 has their King on a portal square and
player 2 has a pece on the corresponding portal square on the other board.
Player 1 moves a piece other than their King.

It is possible that both players may checkmate each other simultaneously.
In this case the game is considered a draw.

Written by David Howe. (The first line was written by Hans Bodlaender.)
WWW page created: May 6, 1997.
﻿